Many types of tamper indicating devices have been developed in the prior art. Among the most common are those using adhesive tapes which deteriorate in some manner when the tapes are detached from a surface. As an example, tapes with lacerations have been used where the tapes break apart into sections when an attempt is made to lift the tape from a surface. Also, adhesive tapes with very strong adhesives have been used where the tape shreds during detachment. As another example, adhesive tapes comprised of a substrate backed by adhesive with a fragile intermediate printed layer between the substrate and the adhesive have also been used where the printed layer detaches from the substrate and remains attached to a surface when an attempt is made to lift the substrate away from the surface. A variant on this uses selective portions of the printing which detach from the substrate to further communicate attempted tampering.
These adhesive tape devices are generally: messy, easy to defeat, do not necessarily make it obvious when tampering has occurred, and only indicate the grossest of tampering.
Tapes, packaging and containers using chemicals which change color or appearance in response to tampering attempts have also been tried. Depending on the embodiment, these have exhibited drawbacks including: having toxic chemicals which are incompatible with foods and medicine, releasing unpleasant odors, not reacting instantly, and not making it obvious when tampering has occurred.
Tampering indication devices of the present invention improve over these and heretofore known devices in the general field in ways apparent from reading the appended specification and claims.